Japan Patent No. 4038685 proposes an actuator element operable in air or in vacuo, wherein the actuator uses a gel of carbon nanotubes and an ionic liquid as an active layer that is electroconductive and elastic.
A conventional actuator element using such carbon nanotubes is excellent in that the initial speed of deformation is high. However, it is possible that the displacement is reduced when a voltage is applied for a long time, and that the element gradually deteriorates and the amount of deformation decreases when current is applied repeatedly.